The La Liga giants have been locked in talks with Spurs all summer but, despite a world-record transfer fee of £85m being offered, an agreement appears to be a long way off.
Madrid's current stance is that they are only willing to increase their bid if they can spread payments over a number of years. That attitude has left Spurs frustrated.
Meanwhile, United's attempts to bring in a marquee signing this summer have yet to bear fruit.
Furthermore, England striker Wayne Rooney has expressed his desire to leave Old Trafford, which has only strengthen calls for manager David Moyes to make a big-money acquisition. Bale, who Spurs value at around £110m, would certainly be that.
United would have no intention of meeting Tottenham's valuation, but they may be able to tempt Spurs with a part-exchange deal.
Although Bale has his heart set on a move to the Bernabeu, it is entirely plausible that he could be persuaded to join United.
After all, a switch to Old Trafford would tick a lot of boxes. It would see him gain a significant pay rise and allow him to compete in the Champions League.
It would also give Bale the opportunity to add medals to his personal trophy cabinet.
While Bale has been showered with personal honours, including two PFA Players' Player of the Year awards, he has yet to win a single team title.
His only cup final appearance to date came in 2009 when Spurs finished as runners-up to United in the League Cup at Wembley.